1. Field of the Invention
This invention relates to roof vents, and more particularly for vents adapted for use on a tile roof.
2. Description of the Related Art
Known systems for venting roofs employ vents that are substantially formed of a single material. Some roof-vents are formed substantially of plastic, which is inexpensive and highly impact resistant, but degrades relatively easily when exposed to rain, snow, and the sun. In particular, the cover of a roof-vent is continually exposed to the elements and may degrade more rapidly than the rest of the vent. Other roof-vents are formed substantially of metal, which is more resistant to the elements but is expensive and susceptible to rust, denting, and other damage during transport and installation.
Some buildings include “stack vents” (i.e., pipes or ducts) with lower ends terminating in rooms likely to have higher pollutant levels, such as kitchens, bathrooms, and laundry rooms, and upper ends extending vertically through the roof. These stack vents are also sometimes referred to as “soil vents.” The stack vent typically extends upward through the ceiling of the room and eventually through the roof of the building, terminating at an upper open end. The stack vent typically also extends upward through other rooms and/or an attic of the building.
The prior art teaches roof-vents that can connect with various sizes of stack vents. Examples of such vents include U.S. Pat. No. 4,399,743 to Izzi, Sr. and U.S. Pat No. 5,081,914 to Mejia. Izzi and Mejia teach structures that are integral with a vent cap and which have fittings of a few discrete sizes for receiving a few different sizes of stack vents. These arrangements preclude connection of the vent to stack vents having sizes other than those conceived in the original design. The prior art also discloses roof vents that reside and blend in with a roof, while connecting directly to the upper end of a stack vent. For example, U.K. Patent Application Publication No. 2 317 947 A to Hensey et al. discloses a covert roof ventilator manufactured by rotation molding from plastics material and provided with an upper wall of shape complementary to roof tiles and an apertured lower wall.